1. Field of the Invention
The present invention relates generally to tracking systems for tracking the location of stolen articles, and more particularly, to a tracking unit for aiding law enforcement officials in apprehending thieves and recovering stolen monies or other property.
2. Description of the Relevant Art
Security packs, or “dye packs,” are known in the banking and security field for assisting law enforcement officers in apprehending bank robbers and recovering stolen currency. These security packs are often disguised as bundles of currency and are handed out by bank tellers to bank robbers in the course of a robbery along with genuine, indistinguishable banded bundles of currency. The disguised security packs, though having the appearance of a banded bundle of currency bills, actually contain electronics used to trigger various compounds that can aid in apprehending the bank robber, including tear gas, smoke, and a dye that stains the robber and any other currency taken during the robbery. Various United States patents describe such security packs, including U.S. Pat. No. 4,511,888 to Bernhardt; U.S. Pat. No. 4,559,529 to Bernhardt; U.S. Pat. No. 5,196,828 to Keniston; and U.S. Pat. No. 5,485,143 to Keniston. While each of these dye pack systems includes features that enhance the effectiveness of such security packs, these known systems do not permit law enforcement authorities to track movements of a bank robber once the robber is out of visual sight.
A currency security pack has been sold in the past under the trademark “ProNet” which emits a radio frequency signal for tracking purposes. However, the “ProNet” system requires that law enforcement officers use several radio receivers to triangulate on the emitted radio signal in order to determine the location of the security pack. While such a system can be helpful if the general location of the suspect is already known, law enforcement authorities often receive insufficient warning of the robbery to permit such tracking systems to be put into operation quickly enough to locate the robber.
U.S. Pat. No. 5,223,844 to Mansell, et al., assigned to Auto-Trac, Inc. of Dallas, Tex., discloses a vehicle tracking and security system for use in the event of a vehicle theft, vehicle breakdown, or other emergency. Mobile units installed in the vehicle include a GPS signal receiver for receiving location data, as well as a cellular telephone transmitter for transmitting location information onto a cellular telephone communications link.
U.S. Pat. No. 5,392,052 to Eberwine discloses a system to assist aircraft search and rescue workers to locate missing aircraft in the event of an emergency. The device includes both a GPS receiver and a radio modem transmitter. In the event of an emergency, the device transmits current time, craft ID, and position data in a data packet.
Applicant is also aware of a security system marketed under the brand name “LowJack” that is installed in automobiles, and which transmits some form of radio and/or telephone signal to help locate a stolen automobile; Applicant believes that U.S. Pat. Nos. 5,557,254 and 5,682,133, both issued to Johnson, et al., and both assigned to Mobile Security Communications, Inc. of Norcross, Ga., disclose the aforementioned tracking system used in the “LowJack” vehicle locating system.
All of the devices described above are fairly large in size, and are typically configured to transmit the location of a vehicle to a remote location. U.S. Pat. No. 5,266,958 to Durboraw, III, and assigned to Motorola, Inc. of Schaumburg, Ill., discloses a somewhat smaller hand-held compass device that uses GPS signals to derive current heading information, but it does not appear that this device transmits any data to a remote location.
U.S. Pat. No. 6,121,922 to Mohan, and assigned to Veridian ERIM International, Inc. of Ann Arbor, Mich., purports to disclose a tracking system that includes a miniaturized module that can be hidden in small spaces, such as on the user's person, and which can transmit location data to a remote monitoring location. The disclosed unit is described as including a global positioning satellite receiver and related antenna, a communications transceiver, a controller, and a rechargeable battery, all mounted on a thin substrate. The Mohan patent specification states that the disclosed device is small enough to permit “implantation and covert operation in articles that are to be tracked (e.g., drugs, currency, artworks, etc.).” However, Mohan does not disclose the concealment of such a device within a disguised bundle of currency, nor does Mohan explain how such a device could actually be incorporated within a disguised bundle of currency.
In addition, the aforementioned patent to Mohan notes that a loss of signal can occur due to structural or natural interference, as might be due to buildings or terrain, for example. This loss of signal can occur because the GPS navigational signals can no longer be received by the mobile module, and/or because the mobile module is unable to effectively transmit over the communications link to the remote monitoring location.
Accordingly, it is an object of the present invention to provide a tracking unit which may be disguised as banded stack of currency bills that is capable of communicating its location to a remote monitoring station following a bank robbery.
It is another object of the present invention to provide such a tracking unit that derives location coordinates from GPS navigational signals transmitted from overhead satellites.
Still another object of the present invention is to provide such a tracking unit that can transmit such location coordinates to a remote location using conventional cellular telephone communication links.
A further object of the present invention is to provide such a tracking unit that can be tracked locally, as within a building, once such tracking unit is no longer able to detect and/or transmit location data over a conventional cellular telephone communications link.
A further object of the present invention is to provide a compact tracking unit that can be used to track the location of stolen property.
These and other objects of the present invention will become more apparent to those skilled in the art as the description thereof proceeds.